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IAAR-24-99 16 39 Fram WOODVARD CLYDE ¢ T-135 P 06/34 lob-462 <br /> The evaluation of the sample collsetion mechanism(the KABIS Sampler)begins with a critical comparison of a <br /> common check-valves baiter,the highest rated sampler mechanism reported by Barcelona,of al Fourteen criteria <br /> were developed by Barcelona at at ,and are presented in Table 2 For the purposes of this evaluation,each dovice <br /> is rated according to the listed cntona and all rating scores are computed to tho mean The mean score is than <br /> compared to the mean score of the Barcelona ratings (1984)and a"weightod"average is demvsd The respective <br /> sampler rating is then compared to a weighted average on the basis of ono standard deviation above or balow tho <br /> over-all weighted average The cheat-valve bailer rocowed a score of 2 71 out of a possible 3 on the rating scale <br /> The only calculation evaluation for pumping mechanisms presented in this level of evaluation is the calculated flow <br /> based on the average mean horad pressure over the available flow area <br /> This level evaluated the range of utility and the necessity of purging the well prior to sampling when using the KAKIS <br /> Sampler under vanous hydrogeologic,and contaminant conditions The test consisted of sampling eight to ton <br /> groundwater monitoring wells from a variety of geologic and hydrologic regimes.at various depths,and for specified <br /> organic contaminants,physical parameters,and gases A single site was selected and a total of twentyfour samples <br /> Tolenpre-purge hyl-be z no,andtthe isomerswere iected The ofvf Wene(EPAA Method 8ammaters;of0 0,)were among the those addresseEPA Method d 180.1),Benzene,Bthe testi <br /> Ther®parameters are identified in TABLE 3 <br /> Since this testing was performed not on a"bunch-scalp"apparatus, but rather on real environmental problems, in the <br /> field,the level-a test runs began with site selection The KAKIS Sampler was tested ander two hydrogeologic <br /> condition, high flow(K=>5 X 102)and low flow(K=>2 43 X 10-2) The representative depositional environment was <br /> comprised,generally,of well sorted sands(fluvatile),with pockets of deltaic sandy clays <br /> The Feld site was selected for the particular contaminant and the currently known concentration range to be X500 <br /> ® parts per billion(ppb).Analyses were performed according to EPA Analysis protocols as doscribed in Table 3 <br /> The following field method was employed <br /> 1,first the well to be sampled was identified and the well construction diagram consulted to determine position of the <br /> screened interval.borehole size,and sand pack information, <br /> 2 next the well was openers and physically gauged to determine current hydrogeologic conditions(ie ,depth to water <br /> and presence of free product), <br /> 3 next the KAKIS Sampler was used to sample the groundwater at a point approximately 4 foot below the screened <br /> Interv&I (50lution chemistry parameters were field checked for temperaturu, pH,and EC), <br /> 4 the well was then purged of 3 well volumes(Including casing and sand-pack Volumes)and allowed to return to <br /> >90%of its original volume(determined by gauging), <br /> S a 32"disposable check-valve bailer was then be used to collect a sample. <br /> 6 next the KAB1S Sampler was again used to collect a sample urimadiatialy follawring sample collection by the bailer <br /> (solution chemistry parameters were again field checked for temperature, pH,and EC), <br /> 7.The well was then recapped and the sampling round proceeded to the next well <br /> . o21 <br /> i3/ iM 4 21 PM <br /> 3or14 <br />